Quiz #2 - Chemical Reactions, Elements, Compounds, and Mixtu

What is evidence that a chemical reaction has occured?

• Shredding paper

• Blue & Red paint mixing to make purple paint

• a new gas is observed in the form of bubble

• a phase change occurs

Julia & Jillian were enjoying the fireworks when they got into a chemistry argument. Julia insisted that the fireworks were the result of a chemical reaction. Jillian disagreed. What would you tell them to solve this argument?

• It is a change of state, solid to gas, due to the addition of energy.

• It was a physical reaction since the fuse was lit and heat was produced.

• The color changes and the release of energy indicate a chemical reaction.

• It is an endothermic reaction because energy was added.

Evidence of a chemical change does NOT include

• producing a gas.

• change in color.

• change in shape.

• change in temperature.

Which model represents the chemical formula NO_2, nitrogen dioxide?

• A

• B

• C

• D

Boiling Water (select the correct answer)

• Physical Change

• Chemical Change

What evidence of a chemical reaction do you see in the picture?

• bubbling (bubbles)

• color change

• precipitate

• heat

Which of the following are evidence(s) of a chemical change that you see in the picture? (Select all that are correct.)

• giving off light

• wood

• camping

• temperature change

Production of Gas or Bubbles is evidence of a

• Physical Change

• Chemical Change

How many atoms does this chemical formula have?

• 4

• 2

• 3

• 1

How many elements create chocolate?

• 3

• 22

• 4

• 21